Re: plenum volume

["Kevin Reynolds" <kereyn@gte.net>]

A plenum full of other questions.

I've seen a few people who have mentioned removing the EGR tunnel. Even
though both sides share the common plenum I wasn't sure if there was enough
crossover between the two sides to see an improvement by doing so.
Do you feel there is a lot of sharing between the two sides?
I have been considering removing the lip on the swirl plates that cuts in
toward the fins and maybe reducing the size of the blades by 1/8" or so.
Have you done any mods to the swirl plates, their angles or size?
I like your idea of unshrouding the ports by cutting back the roofs, but
what do you mean by opening the outside pockets?
When you went to the larger butterflies did you have any work done to the
TBI opening? I was talking to a local shop that does carb and machine work,
and he seemed to think that enlarging the butterflies without working the
radius would limit the full flow benefits of the larger butterflies!
On camshaft selection. I was talking to a gentleman at Lingenfelter
Engineering a while back and was surprised by two things. One, when I asked
his ideas on my X-fire project he didn't immediately tell me to use it for a
boat anchor. Second, out of two cams they carry (214 @ .050 duration and 224
@ .050 duration) he recommended the larger and said not to use the smaller.
Since most of the time (after the boat anchor response) the recommendations
I get are to go 202 duration or smaller due to the "crappy small ports" I
was surprised. His feeling was that the longer duration is a benefit(within
reason) on the X-fire. His feeling was that due to the long runners and
small port size they don't flow as much are as quickly and need the
additional time open to fill the cylinders. Since you seem to be running a
cam in this range I was wondering if that was your thinking as well?

Thanks for the feedback.

By the way, I saw the various post on this list and hope you are doing well,
and wish you a Happy New Year.

Sincerely,

Kevin R




I have sone extensive porting mods to the cross fire manifold.  Making a
1/4" thick spacer for the lid made a large difference (BTW, I'm running a
355 CID).  Much better high rpm breathing.
Also, ground out the ERG tunnel.  Opened up the outside pockets, and cut
port roofs back 1/8" also.   With enough cam 2" butterflies also help.
   BTW run it with a 1227747.  I some wotk but with the info from
programming 101 makes it real sweet.
Grumpy

Kevin R